Task 8 Brain: lobes and hemispheres, crevices and bumps Flashcards
Edwin smith papyrus
papyrus from ancient Egypt that contains short descriptions of the symptoms and treatment of different forms of brain injury
Plato
saw the soul in the brain, divided in three parts one in the brain for thoughts, one in the liver for hunger, one in the heart for sensation
Aristotle
heart was the seat of the soul
Galen
was interested in the brain and described it by animal spirit and ventricles
Animal spirit
spirits that were thought by Galen to travel over the nerves between the ventricles in the brain and the body
Ventricles
apertures in the middle of the brain, which for a long time were thought to contain perceptions, memories and thoughts; seat of the animal spirits
Descartes
proposed a simple loop, in which stimulated nerves caused the release of animal spirits in the ventricles, which, in turn, caused efferent nerves and muscles to act
renaissance
o Differentiation of the three ventricles with different functions e.g. memory
17th and 18th century
o Focus switched on the brain instead of ventricles, more specific white and grey matter (memory)
o Increased interest in reflexes
The discovery in the cerebrospinal axis (19th)
you don’t need cerebral activity to use reflexes because they are mediated by subcortical structures
19th century
breakthrough for neuroscience
reflex arc (growing impact of the reflex) 19th
explains the mechanism involved in involuntary movement elicited by sensory stimuli, discrimination between afferent and efferent nerves (Hall)
Brain equipotentiality theory (19th)
all parts of the brain have equal significance and are involved in each task; first thought to apply to the complete brain; since the nineteenth century limited to the cerebral hemispheres) before 19th century
Localisation theory (19th)
brain processes are localised meaning that only part of the brain underlies a particular mental function (proved by Borca and Wernicke)
The discovery of nerve cell (19th)
The finding that the grey matter consist of billion of cells and that the white matter and the nerves were the tails (axons) of these cells
Availability of better microscopes
New techniques to stain the brain tissue (colouring thingi)
The disentangling of the communication between neurons (19th)
Brain network consists of individual cells, called neurons (Ramon y Cajal)
Electricity within neurons but chemical between (synapse)
• Was first demonstrated on a frog leg and then on a electrical fish, and proved by squid neurons because they are so large
Synapse is discovered and the chemical reaction between them (neurotransmitter)
• Helmholtz stated that because reactions are not that fast it could not be only electricity
Franz Josef Gall (19th)
proving by dissection the crossing of the pyramids and establishing the distinction between grey and white matter
Identified 27 human faculties and associated them with particular brain centres
Neuro revolution was induced by him
Edward Hitzig Gustav Fritsch (19th)
discovered the location of the somatosensory cortex and the somatotopic organization of it
Localisation studies in the world wars (20th)
more precise bullets let to more specific brain injuries from which they could determine the function of the damaged brain parts
Neuropsychology
was studied more by psychologists in the second half of the 20th century and first consisted in tracing brain damage to behavioural consequences
Issues which cognitive neuropsychology fought
o First issue of former investigations, it is difficult to localise different functions only based on damage to the human brain, second the findings rarely went beyond a list of symptoms displayed by various patients
o More focus on information processing
Cognitive neuropsychology
refers to research dealing with the consequences of brain injuries for the information-processing models proposed the cognitive psychologists
The birth of neuroscience
o Due to the new brain imaging techniques, it was possible to observe brain activity during performance of different tasks
Cognitive neuroscience
The scientific study of the biological mechanisms underlying cognition; largely based on brain imaging techniques
Critics on cognitive neuroscience
only localisation purposes and not usable for explaining information-processing theories
New findings
Several regions are needed to perform actions, were more able to clearly define purpose compared to injury cases, processes that were elicited by a stimuli could be traced efficient
Cognitive neuropsychiatry
subfield that tries to understand consequences of metal disorders in terms of breakdown in the cognitive models of normal psychological functioning
Single cell recording
invasive and one of the first measurements
EEG recording
Hans Berger put electrodes on the head to measure electrical signals (named alpha and beta waves)
ERP
measuring brain activity with EEG in combinations to certain events
MEG
measurement of the electrical brain activity by means of measurement of the magnetic field around the head; is one of the most promising brain imaging techniques, because it has the potential of both a high temporal and spatial resolution
PET
brain imaging technique based on measurement of a radioactive tracer injected into the bloodstream
fMRI
brain imaging technique based on the measurement of blood with oxygen vs. blood without oxygen; currently the most popular imaging technique (low temporal resolution)
TMS
stimulation of a brain region by means of a coil placed on the head; allows temporary interference with the processing of a small part of the brain
Development of experiments
o Experiments with control groups and standardized forms were established and compared with statistical methods
Wigan
• Stated that both hemispheres are idiosyncratic brains, each has its own memory with different preferences and interpretations
o When one half is damaged it might occur that the other half is taking control which leads to extraordinary behaviour
o Corpus callosum had no importance to him
o Each brain houses independent consciousness
Because of this the things we can do simultaneously are limited to two
• Wasn’t really important whether back in the time, later it was found that both hemispheres have a different set of abilities so he became a forerunner until it was discovered that he meant something different
Capgras delusion
Thinking that somebody in your close surrounding is replaced by a look-alike
no loss of face recognizing abilities but the emotional connection (e.g. amygdala) might be impaired
Cerebrocentric
The soul is placed in the brain
Cardiocentric
The soul is located in the heart
Associationism
view in terms of associating representations in different brain regions (Wernicke)
Connectionism
put emphasis on the connections between regions
Broadman
: invented architectonic map and emphasised on cell differences in the brain and differentiated by this different parts of the brain (50 areas and still used for localisation today)
